Multicore TTC-LF consists of lead-free grade solder powder and flux, formed into shape of thick disk for cleaning and de-wetting soldering irons. It can clean heavily oxidized metal surfaces such as copper and iron-plated soldering tips. Users wipe tip of iron across its surface to produce local melting, and then wipe on damp sponge. Suited for lead and lead-free applications, powder/flux has activators that thermally decompose into inert components.